We have a 2017 Explorer with the 2.3 EB with a little over 62,000 miles. We bought it new. Thank goodness for inline 4 cylinder engines when it comes to changing spark plugs. Cylinders 1 through 3 were creaky dry upon removal but came out just fine. Cylinder 4 wasn't as creaky and I found out why, oil on the threads, but not on the firing end of the plug. All the ceramics were light tan, even #4. The gaps were all .030, well within the .027-.031 Ford spec. I replaced them with the recommended Motorcraft plugs, SP-537/CYFS-12Y-2 Iridium plugs. I gapped the new plugs at .027. For a turbo DI engine I was pleasantly surprised how little wear there was at 62,000 miles on the plugs. They could have easily gone much further wear wise but I was leery about removing them at the recommended mileage without having a difficult time. I used anti-seize and reduced the torque 15% from the suggested maximum.